It's devils food box cake with nutella frosting and I cut a small hole in each of them and added smashed up strawberries to break up all the chocolate. The Batman and Robin symbols are all made out of melty chocolates that I got at Joann's.

All I did was print out the symbols and then put wax paper over then and then melted the chocolates in plastic lunch bags and cut the tip of teh corner off and traced them out. :3